Metabolites of sphingomyelin, sphingolipids such as ceramide, sphingosine or sphingosine 1-phosphate, participate in intracellular signal translation, such as apoptosis, cell proliferation, PKC inhibition, etc., and therefore the metabolites have drawn the great attention. From the fact, the enzyme, sphingomyelinase which converts sphingomyelin to ceramide is considered to be a very important enzyme.
However, the mechanism of action and higher-order structure of this enzyme is not elucidated and therefore, such a substance as useful for a resolution of the mechanism has been desired.